Essential Oils as an Alternative to Antibiotics to Reduce the Incidence and Severity of Necrotic Enteritis in Broiler Chickens: A Short Review
Makenly E. Coles1, Brittany D. Graham1, Juan D. Latorre1, Victor M. Petrone-Garcia2, Xochitl Hernandez-Velasco3, Inkar Castellanos-Huerta4, Xiaolun Sun1, Billy M. Hargis1, Saeed El-Ashram5, Awad A. Shehata6, Guillermo Tellez-Isaias1*
1Department of Poultry Science, University of Arkansas Agricultural Experiment Station, Fayetteville, USA.
2Facultad de Estudios Superiores Cuautitlan, Universidad Nacional Autonoma de Mexico (UNAM), Cuautitlan Izcalli, Estado de Mexico, Mexico.
3Departamento de Medicina y Zootecnia de Aves, Facultad de Medicina Veterinaria y Zootecnia (FMVZ), UNAM, Cd. de Mexico, Mexico.
4Programa de Maestría y Doctorado en Ciencias de la Producción y de la Salud Animal, FMVZ, UNAM, Cd. de Mexico, Mexico.
5College of Life Science and Engineering, Foshan University, Foshan, China.
6Prophy-Institute for Applied Prophylaxis, Bönen, Germany.
DOI: 10.4236/fns.2023.143016   PDF   HTML   XML   94 Downloads   445 Views  


Due to the removal of antibiotic growth promoters (AGPs) and consumer pressure for antibiotic-free (ABF) or no antibiotics ever (NAE) poultry production, there is a need for sustainable alternatives to prevent disease in commercial poultry operations. Without AGPs, there has been a rise in diseases that were traditionally controlled by subtherapeutic levels of antibiotics in the diet. This has impacted the health of commercial poultry and has been a significant cost to poultry producers. To mitigate this, the industry has started to investigate alternatives to antibiotics to treat these forthcoming health issues, such as necrotic enteritis (NE). NE is an enteric disease caused by an over proliferation of toxigenic Clostridium perfringens (CP) in the gastrointestinal tract. Although CP is a commensal in the avian intestinal tract, dysbiosis caused by inflammation and impaired intestinal integrity facilitates uncontrolled replication of CP. Infectious agents, such as Eimeria maxima, appear to be a predominant predisposing factor that promotes NE. However, non-infectious stressors, including dietary changes, have also been associated with NE to some degree. As a result of increased pressure to restrict the use of antibiotics, there is a need for research evaluating the efficacy of alternatives, such as plant-derived essential oils, as potential tools to mitigate NE in commercial poultry flocks. The aim of this study is to review the effects of essential oils as an alternative to antibiotics to reduce the incidence and severity of necrotic enteritis in broiler chickens.

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Coles, M. , Graham, B. , Latorre, J. , Petrone-Garcia, V. , Hernandez-Velasco, X. , Castellanos-Huerta, I. , Sun, X. , Hargis, B. , El-Ashram, S. , Shehata, A. and Tellez-Isaias, G. (2023) Essential Oils as an Alternative to Antibiotics to Reduce the Incidence and Severity of Necrotic Enteritis in Broiler Chickens: A Short Review. Food and Nutrition Sciences, 14, 233-257. doi: 10.4236/fns.2023.143016.

1. Introduction

Over the last few hundred years, humans have influenced the evolution of multiple animal species and different ecosystems involved in animal production [1]. This approach has led to the genetic change of domestic animals and has undoubtedly been driven by agriculture. The most important genetic changes in poultry production have occurred in the previous 60 years. Modern broiler chickens are likely the clearest example of these genetic improvements. Newborn chicks grow 31% (55 g/bird) on day one, and 5902% (2521 g/bird) on day 35 [2]. Intensive genetic selection, diet, health, and management initiatives have led to these achievements. Nonetheless, maintaining the integrity of the gastrointestinal tract (GIT), the primary organ responsible for digestion and nutritional absorption, is critical for production. Because feed conversion accounts for over 70% of the cost of production in poultry and animal enterprises, subclinical coccidiosis and necrotic enteritis in chickens are more costly than acute infections (Figure 1). As the growing period of broilers shortens and feed efficiency improves, so do health and nutrition programs. Therefore, increasing the importance of a well develop intestinal epithelia and a balance host-diet-microbiota interaction that influences gut health and overall health and productivity.

Essential oils (EO) have received a lot of attention as nutraceuticals in livestock production in recent years, primarily as an alternative to antibiotic growth promoters (AGPs) worldwide. Essential oils are secondary metabolites derived from various plants with well-documented antibacterial, antiviral, antifungal, antioxidant, digestive stimulant, and immunomodulatory properties [3] [4] [5] [6] [7]. Some EO are used in conjunction with other phytochemicals to improve poultry performance [8]. As a result, EO have played a critical role in reducing the increased incidence of coccidiosis and necrotic enteritis (NE) caused by the removal of ionophores and AGPs. Because NE is a multifactorial disease caused by Eimeria spp. and Clostridium perfringens, EO is frequently combined with other strategic products such as probiotics, prebiotics, organic acids, and enzymes to modulate the intestinal microbiota and immune system of birds [9] [10] [11]. The aim of this study is to review the effects of essential oils as an alternative to antibiotics to reduce the incidence and severity of necrotic enteritis in broiler chickens.

Figure 1. Even though necrotic enteritis is a multifactorial disease, Eimeria maxima has been considered a primary pathogen in the clinical and subclinical outbreaks of necrotic enteritis. (a) Mucosal and submucosal jejunum with infiltration of inflammatory cells, ulceration, necrosis, and the presence of E. maxima oocysts. Hematoxylin and eosin staining. NE causes macroscopic (b) ballooning of intestines and (c) extensive sloughing of the intestinal mucosa and hemorrhaging. (d) While clinical and acute outbreaks can induce severe mortality, the global economic losses are due to (e) subclinical necrotic enteritis, affecting all performance parameters. (Images courtesy of Dr. Victor M. Petrone-Garcia and Created with

2. Importance of GIT Health in Poultry

The GIT is home to a varied microbial community known as gut microbiota [12], outnumbering somatic cells by tenfold, with 300,000 genes compared to 23,000 genes in chickens [13] [14]. The enteric nervous system (ENS) has approximately one hundred million neurons and is referred to as the “second brain” of metazoans because of its importance in digestion [15]. Approximately 80 percent of the immune cells in the body are found in the gut-associated lymphoid tissue (GALT). The Bursa of Fabricius, a lymphoid organ that is critical for B-lymphocyte growth and proliferation in avian species, is a component of the GALT [16]. As an astonishment, the GALT comprises 80 percent of the plasma cells that are responsible for the production of secretory immunoglobulin A (IgA), the far more prevalent immunoglobulin [17].

A range of physiological processes, including secretion, absorption, digestion, and gut motility, are mediated by enteroendocrine cells (EECs), which also play a role in the etiology of intestinal mucosa atrophy and malignancies, both within and beyond the GIT [18]. Gastrin, secretin, cholecystokinin, insulin, and glucagon were among the first GIT hormones to be discovered in humans [19]. The discovery of more than 50 gut hormones and bioactive peptides today confirms that the gut is the body’s largest endocrine organ, performing an extensive spectrum of endocrinological, neuroendocrine, autocrine, and paracrine functions, as well as a variety of other roles [20]. Enterochromaffin cells, a subset of several EECs, produce 90% of the neurotransmitter serotonin (5-hydroxytryptamine), which plays multiple biological roles in temperament, perception, reproduction, vasodilation, gut motility, wound healing, and vasoconstriction [21]. Surprisingly, the gut microbiome modulates serotonin and other EEC-produced mood neurotransmitters like dopamine, oxytocin, and endorphins [22] [23] [24]. Published research have shown that in humans, illnesses of the brain (such as schizophrenia, depression, Alzheimer’s disease, Parkinson’s disease, and autism) are associated with the kind of microbiota prevalent in the GIT [25] [26]. The cliché “gut instincts” holds true in this case [27].

For more than a century, Eli Metchnikoff, the Nobel Prize-winning father of innate immunity, offered the breakthrough idea of ingesting live bacteria to boost health by modifying the intestinal microbiota [28] [29]. Antibiotic resistance in bacteria (sometimes known as “superbugs”) is a major problem in medicine and agriculture around the world. As the number of antibiotic-resistant bacteria grows, this concept is becoming increasingly relevant [30]. According to recent research, nutritional approaches may be effective alternatives to antibiotics in some cases [31] [32] [33] [34]. In addition to increasing animal health, welfare, and production, boosting disease resistance in antibiotic-free animals is an important task in enhancing food safety. The gut microbiota influences the host’s biology, metabolism, nutrition, immunity, and neuroendocrine system [35] [36]. Short-chain fatty acids, gastrointestinal hormones, enteroendocrine and immune cells all play a role in these effects [37]. The enteric nervous system and hormonal networks control GIT motility, which is impaired in functional GIT diseases [38]. The neuroendocrine network that connects the brain, the ENS, gut microbiota, and the GALT has a significant impact on the delicate intestinal epithelial barrier [39] [40]. This barrier, which consists of a single layer of enterocytes with tight intercellular junctions, regulates the balance of tolerance and immunity to non-self antigens [41]. Hence, gut integrity is critical in maintaining a healthy balance of health and disease [42]. To keep the system in survival mode, chronic stress and chronic intestinal inflammation divert significant biological resources away from development and reproduction. Perhaps a more comprehensive definition of “gut health” should include the harmonious interaction of the microbiota-brain-gut axis [35] [43] [44].

All biological and physiological processes maintain the various microbiomes that live on mucosal surfaces in balance [45]. Dysbiosis (loss of symmetry of the GIT microbiota) leads to loss of intestinal integrity [46]. Dietary ingredients and the viscosity of gut contents influence microbes in the small intestine [47]. Animal producers who have eliminated antibiotics from their production systems may use a combination of alternative products, improved management methods, stringent biosecurity, and successful immunization programs to achieve their health and productivity goals. However, chronic stress and persistent inflammation still harm modern animal production operations. Any source of chronic stress, whether biological, physical, chemical, toxic, or psychological, will cause oxidative stress and, if unabated, chronic intestinal and systemic inflammation [48] [49] [50]. Chronic intestinal and systemic inflammation opens up the gut to opportunistic bacteria such as C. perfringens.

2.1. Clostridium spp. in the GIT

To maintain gut homeostasis, a complicated mutualistic symbiosis maintains the host-microbiota connection [51]. Commensal Clostridia (Class) in the Firmicutes (Phylum) make up a large proportion of the gut microbiota [52]. Clostridial spp. begin colonizing the intestine at hatch, subsist near intestinal cells, and play an important role in altering gut physiology and immunology [52]. Clostridium (Genus) contains over one hundred beneficial species, and only a few are pathogenic [53]. They represent the most significant butyric acid-producing organisms in the GIT [53]. Commensal Clostridia play an active role in maintaining overall gut function [52]. Hence, distinguishing beneficial Clostridial species from potentially virulent ones, like Clostridium perfringens, is critical [54]. Clostridial cluster IV contributes to up to twenty percent of bacteria present in humans [55]. Clostridium clusters XIVa and IV members consistently decreased in patients with gut inflammation [56]. This implies that these organisms are vital to gastrointestinal homeostasis [54]. Clostridiales (Order) also increased mucosal tolerance to commensal microbiota by boosting IL-10 and transforming growth factor-beta expression levels in the gut [57]. Furthermore, Clostridiales such as Ruminococcus spp., Faecalibacterium spp., and Lachnospiraceae spp. are the remarkable bacteria that produce butyrate [58] [59], inducing profound physiological reactions in the gut [60]. Clostridium cluster strains IV and XIVa are great inducers of T-regulatory cells and constitute a novel therapeutic alternative for intestinal inflammatory diseases [61]. Interestingly, probiotics have been demonstrated to cause significant alterations in butyrate and other key SCFA, which have a considerable impact on gut physiology and immunology [62] - [67]. Commensal Clostridium bacteria clearly are vital in gut homeostasis [52]. However, commensal Clostridial spp. such as C. perfringens rapidly proliferate when the broiler’s epithelium is damaged [68]. There are predisposing factors that increase C. perfringens overgrowth such as nutritional components [69] and coinfections with Salmonella spp. [70] or Eimeria spp. [10] (Figure 2). Mucin-2 is the most abundant mucin that is secreted by intestinal epithelial cells [71]. Eimeria spp. have been shown to have an effect on the relative mucin secretion in each area of the GIT [72].

2.2. Necrotic Enteritis

Necrotic enteritis (NE) is caused by the ubiquitous bacterium C. perfringens. C. perfringens is an anaerobic, Gram-positive, endospore-forming, nonmotile, bacterium that can survive and persist in harsh environmental conditions. As the

Figure 2. (a) Mucosal and submucosal jejunum with infiltration of inflammatory cells, ulceration, necrosis, and the presence of E. maxima oocysts. Hematoxylin and eosin staining. (b) Mucosal and submucosal duodenum with infiltration of inflammatory cells, ulceration, necrosis and the presence of Eimeria acervulina oocysts. Hematoxylin and eosin staining. (c) Duodenum and jejunum of a layer hen with necrotic enteritis. The liver shows areas of necrosis and hemorrhages due to liver bacterial translocation and chronic systemic inflammation. (d) Oviduct and ovary from the same layer hen showing hemorrhages and inflammation. (Images courtesy of Dr. Victor M. Petrone-Garcia and Created with

chicken industry has reduced its usage of antibiotics, NE in both its clinical and subclinical forms have become a significant health, welfare, and performance problem [73]. Because NE is a complex disease, that usually includes a co-infection of Eimeria spp. and C. perfringens, management without antibiotics requires sustainable alternative prophylactic or therapeutic strategies [11]. The total global economic cost of NE was assessed to be more than $2 billion dollars in 2000 [74]. The number of broiler chickens produced increased from 14.38 billion in 2000 to approximately 33 billion in 2020 worldwide [75]. It was estimated that necrotic enteritis cost the United States poultry industry $6 billion annually [76].

C. perfringens is grouped into seven toxigenic categories (A-G) producing over twenty toxins [77]. The poultry industry is particularly interested in C. perfringens types A, C, and G [78] [79]. In this process, C. perfringens releases enzymes that break down host tissue, causing more tissue damage, inflammation, and disruption of the intestinal ecology, causing dysbiosis [80] [81] [82]. These C. perfringens strains produce pathogenic toxins including NetB toxin, which has been identified as a major factor associated with NE in broilers [83] (Figure 3). Field outbreaks of NE had one C. perfringens clone prevalent in the intestines of all infected birds, rather than the variety of strains found in healthy bird

Figure 3. C. perfringens types A, C, and G release (a) enzymes that break down host tissue causing (b) inflammation, and disruption of the intestinal ecology, resulting in dysbiosis. NetB toxin, which has been established as a significant contributor in NE in broilers, is present in these lethal C. perfringens strains. Additionally, some C. perfringens strains have shown to produce collagenolytic enzymes that induce an initial pathological change in the enterocytes, contributing to the development of NE. (c) Lesions caused by C. perfringens proliferation and toxin production can be observed macroscopically. (Images courtesy of Dr. Victor M. Petrone-Garcia and Created with

intestines. A single dominant C. perfringens strain associated with NE may be due to bacteriocin production [83]. Intestinal C. perfringens overgrowth has been linked to intestinal mucosa injury, low pH, coccidiosis, nutritional factors, stress, and immunosuppression [83] [84] [85]. Several investigators have evaluated different alternatives to reduce NE such as probiotics, prebiotics, symbiotic, and organic acids [9] [86] [87] [88].

C. perfringens infection alone is not enough to cause necrotic enteritis in broiler chickens. Predisposing factors are a key player in creating the right environment for the proliferation of virulent C. perfringens, producing disease [89]. These predisposing factors can include, but are not limited to, feed ingredients [90], coccidiosis caused by Eimeria spp. [91] , environmental stressors [92], and exposure to Salmonella spp. [70].

2.3. Alternatives to Antibiotics to Control NE

Due to the removal of AGPs and the shift to antibiotic free production systems, research investigating antibiotic alternatives have been on the rise. The incidence of Clostridial-related diseases, including NE, increased with implementation of AGP bans [93]. In an antibiotic-limited or antibiotic-free era, natural alternatives to optimize intestinal health and improve animal wellbeing and performance are desperately needed. Probiotics are live, beneficial microorganisms that have been shown reduce colonization by enteric pathogens [94] [95] [96]. Direct-fed microbials [97], prebiotics [98] [99] [100], organic acids [101], plant extracts [102], essential oils [1] [103], and trace minerals [104] can help to improve intestinal microbial balance, metabolism, and gut integrity. Phytogenics have remarkable antioxidant, anti-inflammatory, antibacterial, and barrier integrity-enhancing assets. For example, supplementation with curcumin, a component in tumeric, reduced the severity of necrotic enteritis [105], salmonellosis [102] [105], and aflatoxicosis [106] in broiler chickens as well as coccidiosis in Leghorn chickens [107]. Additional investigations regarding phytogenics, specifically EOs and gut health are described below.

2.4. Essential Oils

Essential oils (EOs) are a derivative of plants. Revered for their medicinal properties, EOs are natural, volatile compounds usually associated with a strong odor [108]. The mode of action(s) of EOs has been extensively reviewed [109]. EOs inhibit in vitro proliferation of Gram-negative and Gram-positive bacteria by increasing membrane permeability of the cell wall and mitochondrial membranes [109]. Antimicrobial efficiency of EOs is impacted by the compound’s hydrophobicity [110]. In vitro studies show evidence that when compared to standard antimicrobial agents, EOs have a similar effect on the growth inhibition of C. perfringens [111].

EOs have been increasingly popular as feed additives over the last two decades [112] due to their antibacterial, antiviral, antifungal, anti-inflammatory, immunomodulatory, epithelial barrier, microbiota modulation, production performance and anti-hyperlipidemic properties [4] [5] [6] [7] [8] [113] [114] (Figure 4). Lippia origanoides or Thymus Vulgaris L. contains up to 3% essential oil containing monoterpenes, mainly thymol and its phenol isomer carvacrol. Phenolics in essential oil such as caffeic acid, p-cymene-2,3-diol and some biphenylic and flavonoid compounds like flavonoid glycosides, flavonoid aglycones are assumed to contribute various beneficial effects and have been used as a feed additive in poultry diets without adverse effects [115]. However, one of the most remarkable bioactive properties of EOs is their anti-oxidant effect, which prevents lipid peroxidation of the cell membrane and mitochondrial membrane phospholipids, as well as the denaturalization of proteins and DNA, thereby preventing multiple organ failure and other diseases [3] [116].

Some studies found in the literature using EOs instead of antibiotics have shown to reduce the severity of NE through the demonstrated bactericidal activity of EOs against C. perfringens [111] [117]. Other recent studies have revealed a reduction in NE-induced intestinal damage [10] [118] [119] [120] [121], reduction in mortality associated with NE [122] [123], regulation of the intestinal microbial communities [124] [125] [126], modulation of short-chain fatty acids profiles [84] [127], improvement of the morphometric and barrier functions

Figure 4. Carvacrol and thymol are two of the most abundant essential oils present in Lippia origanoides. Both essential oils have been extensively studied due to their anti-oxidant, gut microbiota modulation, immunoregulation, epithelial barrier, antifungal, antimicrobial, antiviral, anthelminthic, hypocholesterolemia, appetite stimulant and increased pancreatic enzyme production, and improving performance properties. (Images courtesy of Dr. Victor M. Petrone-Garcia and Created with

[123] [128], as well as, reduction of oocyst counts [129] [130] and dysbacteriosis [131] [132]. EOs, especially thymol and carvacrol stimulate enzyme secretion and improve digestion, and several studies have shown a substantial impact of EOs on performance parameters and intestinal lesion scores in broiler chickens under different NE models (Table 1).

EOs have been shown to alter the host’s immune response. Dietary inclusion of carvacrol, cinnamaldehyde or oleoresin altered gene expression of intestinal intraepithelial lymphocytes, with dietary oleoresin having the greatest effect on transcriptional regulation [133]. Furthermore, EOs limited pro-inflammatory cytokine production related to C. perfringens or Eimeria spp. challenge [134]. Pathogenicity of C. perfringens was modulated by the inclusion of EOs (25% carvacrol, 25% thymol; 120 mg/kg) in the diet which downregulated in vivo expression of C. perfringens virulence factors: VF 0073-ClpE, VF0124-LPS, and VF0350-BSH [126]. The altered host ileal microbiome composition and C. perfringens virulence factor expression was likely reduced intestinal lesion scores and mortality in broiler chickens [126]. The direct or indirect changes in the gut

Table 1. Impact of essential oils (EOs) on performance parameters and intestinal lesion score in broiler chickens under different necrotic enteritis (NE) models.

*PC: Positive control; ?/sup>ND: Not determined.

microbiome composition associated with EOs treatment is suggested to be a primary beneficial factor related to application of EOs as natural alternatives to antibiotics.

Combinations of EOs and organic acids have synergistic or additive effects that may improve poultry gut health and growth performance [137]. Similar to dietary EOs fed alone, blends of EOs and organic acids alter the composition of the gut microbiota, specifically increasing the abundance of Lactobacillus spp. [137] and SCFA concentration in the gut [142]. As a result, the dietary blends can inhibit the overgrowth of C. perfringens in the gut perhaps lowering the incidence and severity of NE. For instance, encapsulated blends of EOs (thymol, vanillin, eugenol) and organic acids (fumaric, sorbic, malic, citric) have been shown to improve gut health and performance of NE-affected broiler chickens [143]. Similarly, feeding microencapsulated blends of EOs and organic acids (BUTYTEC-PLUS or ACITEC-MC) to broiler chickens placed on used NE litter increased growth performance due to improved intestinal barrier function and integrity [132]. Enteric inflammation associated with NE may have been reduced due to the anti-inflammatory effects of a dietary blend of encapsulated EOs and an organic acid (4% carvacrol, 4% thyme, 0.5% hexanoic, 3.5% benzoic, 0.5% butyric acid) [128]. Additionally, broiler chickens that received the EO and organic acid blend had improved intestinal integrity compared to the non-treated, challenged group [128].

Several investigators have demonstrated that EO supplementation has a positive effect on intestinal microbiota while also improving growth performance [8] [144] [145]. According to their findings, modulating broiler gut microbiota composition and activity with EO is an effective way to improve broiler performance.

Taken together, phytogenic compounds, such as EOs show promise as natural alternatives to mitigate the severity of NE-induced intestinal damage and performance losses. However, factors including the antimicrobial activity of the specific EO evaluated, EO dose, NE challenge model, and methods to determine efficacy of these naturally occurring AGP alternatives must be considered when designing experiments and comparing research findings.

2.5. Brief Overview of Methods to Evaluate Impact of Antibiotic Alternatives on Intestinal Integrity and Enteric Inflammation

Researchers have used different enteric inflammation models to understand the mechanism of action of multiple alternatives to antibiotic growth promoters (AGP) such as EO. Some of the models included nutritional factors [47], management [146], chemicals [147] [148], pathogen exposure [149] and environmental fluctuations [103] as challenge conditions to evaluate the effect of AGP alternatives on enteric inflammation. A non-terminal approach, such as serum fluorescein isothiocyanate-dextran (FITC-d) concentration, can be used to assess intestinal permeability and tends to correlate with bacterial translocation in the liver [150]. For the FITC-d assay, a 4 - 6 kDa FITC-d molecule is utilized since it cannot translocate through an undamaged intestinal epithelium [151]. Thus, an increase in FITC-d in the serum indicates that there has been damage to the intestinal epithelial barrier [151]. Other reliable serum biomarkers, such as antioxidant biomarkers, isoprostane 8-iso-PGF2 and prostaglandin GF2, have been evaluated [107]. Enterocyte biomarkers such as peptide YY, Fenterocellular signal-regulated kinase, citrulline, and mucin 2, as well as immune biomarkers peptide YY, enterocellular signal-regulated kinase, citrulline, and mucin 2, total or specific secretory IgA and interferon-gamma have been utilized [152] [153]. IgA is closely associated with mucosal immunity in mammals and avian species [154] [155]. It is the main immunoglobulin isotype in most mucosal secretions [155]. Therefore, elevated IgA levels can be associated with elevated mucin production and an increased immune response. Interferon-gamma is a pro-inflammatory cytokine associated with intestinal inflammation and gut leakage [156]. Thus, interferon-gamma levels in the serum can be used to assess inflammation. Reactive oxygen species, such as superoxide are free radicals that are created naturally through cellular respiration. Free radical accumulation is damaging [157]. An enzyme, superoxide dismutase catalyzes superoxide into oxygen and hydrogen peroxide [158]. Superoxide dismustase concentration in the sera has been used to assess oxidative stress in broiler chickens [152]. Additionally, gene expression of other biomarkers, such as 1-acid glycoprotein, fatty acid-binding protein, and interleukins (IL-8, IL-1β,), mucin 2, transforming growth factor, and tumor necrosis factor have also yielded promising results [31] [159].

Inflammation alters expression of intestinal tight junction proteins followed by increased intestinal permeability [160]. Futhermore, intestinal morphometric measurements, such as villus height, villus width, crypt depth, and crypt/villi ratio can be used to evaluate gut integrity. An increase in crypt depth and villus witdh was indicative of gut barrier failure in broiler chickens [159]. The I See Inside (ISI) methodology, which employs both macroscopic and histological analyses, has been used to determine the impact of a treatment or challenge on an organs function. This method been used to assess effect of EOs and organic acids on ISI scores in NE-challenged broiler chickens [143].

3. Conclusion

The removal of AGPs or shift to antibiotic-free or no antibiotics ever production in commercial poultry systems has been associated with reduced performance and increased mortality [161] [162] [163]. Diseases that were traditionally treated by subtherapeutic amounts of antibiotics in the diet have increased. This has had a negative effect on the health of commercial chickens and has incurred substantial costs for poultry producers. To counteract this, the industry has begun to explore alternatives to antibiotics for treating impending health problems, such as NE. Even though CP is a commensal in the avian intestinal tract, dysbiosis produced by inflammation and compromised intestinal integrity encourages the uncontrolled proliferation of CP. Infectious pathogens, such as Eimeria maxima, appear to be the most important risk factor for NE. However, any kind of chronic stress, regardless of its origin (nutritional, environmental, physical, chemical, or psychological) that alter the microbiota-brain-gut axis are also linked to NE. Due to their antibacterial, antiviral, antifungal, anti-inflammatory, immunomodulatory, epithelial barrier, microbiota modification, and antihyperlipidemic characteristics, EOs have become more popular as feed additives over the past two decades. Moreover, there are an outstanding number of studies suggesting that EOs are a safe and effective alternative to antibiotics to reduce the incidence and the severity of NE in broiler chickens. In conclusion, EOs can be used in poultry feed, but there are still questions about their action, metabolic pathway, and optimal dosage in poultry that need to be investigated further.

Author Contributions

MEC, BDG, and GT-I developed the conceptualization and wrote the first draft of the manuscript. GT-I drew and edited the figures. VP-G, XH-V, XS, JDL, and BMH participated in design, analysis, presentation, and writing of manuscript. All authors have read and agreed to the submitted version of the manuscript.


All figures were created with Macroscopic photographs of organs with lesions, clinical signs or mortality were taken by VP-G and XH-V. Microscopic photographs were taken by BDG.


Research was supported in part by funds provided by USDA-NIFA Sustainable Agriculture Systems, Grant No. 2019-69012-29905. Title of Project: Empowering US Broiler Production for Transformation and Sustainability USDA-NIFA (Sustainable Agriculture Systems): No. 2019-69012-29905.

Conflicts of Interest

The authors declare no conflicts of interest regarding the publication of this paper.


[1] Coles, M.E., Forga, A.J., Señas-Cuesta, R., Graham, B.D., Selby, C.M., Uribe, A.J., et al. (2021) Assessment of Lippia origanoides Essential Oils in a Salmonella Typhimurium, Eimeria maxima, and Clostridium perfringens Challenge Model to Induce Necrotic Enteritis in Broiler Chickens. Animals, 11, 1111.
[2] Cobb500 Broiler Performance & Nutrition Supplement (2022).
[3] Zeng, Z., Zhang, S., Wang, H. and Piao, X. (2015) Essential Oil and Aromatic Plants as Feed Additives in non-Ruminant Nutrition: A Review. Journal of Animal Science and Biotechnology, 6, 7.
[4] Saadat Shad, H., Mazhari, M., Esmaeilipour, O. and Khosravinia, H. (2016) Effects of Thymol and Carvacrol on Productive Performance, Antioxidant Enzyme Activity and Certain Blood Metabolites in Heat Stressed Broilers. Iranian Journal of Applied Animal Science, 6, 195-202.
[5] Turcu, R.P., Tabuc, C., Vlaicu, P.A., Panaite, T.D., Buleandra, M. and Saracila, M. (2018) Effect of the Dietary Oregano (Origanum vulgare L.) Powder And Oil on the Balance of the Intestinal Microflora of Broilers Reared under Heat Stress (32 °C). In: Scientific Papers: Series D, Animal Science—The International Session of Scientific Communications of the Faculty of Animal Science, University of Agronomic Sciences and Veterinary Medicine of Bucharest, Romania, 77-86.
[6] Zhai, H., Liu, H., Wang, S., Wu, J. and Kluenter, A.-M. (2020) Potential of Essential Oils for Poultry and Pigs. Animal Nutrition, 4, 179-186.
[7] Patra, A.K. (2020) Influence of Plant Bioactive Compounds on Intestinal Epithelial Barrier in Poultry. Mini Reviews in Medicinal Chemistry, 20, 566-577.
[8] Krishan, G. and Narang, A. (2014) Use of Essential Oils in Poultry Nutrition: A New Approach. Journal of Advanced Veterinary and Animal Research, 1, 156-162.
[9] De la Mora, Z.V., Macías-Rodríguez, M.E., Arratia-Quijada, J., Gonzalez-Torres, Y.S., Nuño, K. and Villarruel-López, A. (2020) Clostridium perfringens as Foodborne Pathogen in Broiler Production: Pathophysiology and Potential Strategies for Controlling Necrotic Enteritis. Animals, 10, 1718.
[10] Adhikari, P., Kiess, A., Adhikari, R. and Jha, R. (2020) An Approach to Alternative Strategies to Control Avian Coccidiosis and Necrotic Enteritis. Journal Applied of Poultry Research, 29, 515-534.
[11] Hofacre, C.L., Smith, J.A. and Mathis, G.F. (2018) An Optimist’s View on Limiting Necrotic Enteritis and Maintaining Broiler Gut Health and Performance in Today’s Marketing, Food Safety, and Regulatory Climate. Poultry Science, 97, 1929-1933.
[12] Celluzzi, A. and Masotti, A. (2016) How Our Other Genome Controls Our Epi-Genome. Trends in Microbiology, 24, 777-787.
[13] Wallis, J.W., Aerts, J., Groenen, M.A., Crooijmans, R.P., Layman, D., Graves, T.A., et al. (2004) A Physical Map of the Chicken Genome. Nature, 432, 761-764.
[14] Zhu, B., Wang, X. and Li, L. (2010) Human Gut Microbiome: The Second Genome of Human Body. Protein and Cell, 1, 718-725.
[15] Schneider, S., Wright, C.M. and Heuckeroth, R.O. (2019) Unexpected Roles for the Second Brain: Enteric Nervous System as Master Regulator of Bowel Function. Annual Review of Physiology, 81, 235-259.
[16] Bar-Shira, E., Sklan, D. and Friedman, A. (2003) Establishment of Immune Competence in the Avian GALT during the Immediate Post-Hatch Period. Developmental and Comparative Immunology, 27, 147-57.
[17] Vighi, G., Marcucci, F., Sensi, L., Di Cara, G. and Frati, F. (2008) Allergy and the Gastrointestinal System. Clinical and Experimental Immunology, 153, 3-6.
[18] Gribble, F.M. and Reimann, F. (2019) Function and Mechanisms of Enteroendocrine Cells and Gut Hormones in Metabolism. Nature Reviews, Endocrinology, 15, 226-237.
[19] Bloom, S.R. (1987) Gut Hormones in Adaptation. Gut, 28, 31-35.
[20] Gribble, F.M. and Reimann, F. (2017) Signalling in the Gut Endocrine Axis. Physiology and Behavior, 176, 183-188.
[21] Lund, M.L., Egerod, K.L., Engelstoft, M.S., Dmytriyeva, O., Theodorsson, E., Patel, B.A., et al. (2018) Enterochromaffin 5-HT Cells-A Major Target for GLP-1 and Gut Microbial Metabolites. Molecular Metabolism, 11, 70-83.
[22] Forsythe, P., Sudo, N., Dinan, T., Taylor, V.H. and Bienenstock, J. (2010) Mood and Gut Feelings. Brain, Behavior and Immunity, 24, 9-16.
[23] Liang, X., Bushman, F.D. and FitzGerald, G.A. (2014) Time in Motion: The Molecular Clock Meets the Microbiome. Cell, 159, 469-470.
[24] Mayer, E.A., Knight, R., Mazmanian, S.K., Cryan, J.F. and Tillisch, K. (2014) Gut Microbes and the Brain: Paradigm Shift in Neuroscience. The Journal of Neuroscience, 34, 15490-15496.
[25] Cryan, J.F. and Dinan, T.G. (2012) Mind-Altering Microorganisms: The Impact of the Gut Microbiota on Brain and Behaviour. Nature Reviews, Neuroscience, 13, 701-712.
[26] Sherwin, E., Rea, K., Dinan, T.G. and Cryan, J.F. (2016) A Gut (Microbiome) Feeling about the Brain. Current Opinion Gastroenterology, 32, 96-102.
[27] Tellez, G. (2014) Prokaryotes versus Eukaryotes: Who is Hosting Whom? Frontiers in Veterinary Science, 1, 3.
[28] Gordon, S. (2018) Eli Metchnikoff: Father of Natural Immunity. European Journal of Immunology, 38, 3257-3264.
[29] Kaufmann, S.H. (2008) Immunology’s Foundation: The 100-Year Anniversary of the Nobel Prize to Paul Ehrlich and Elie Metchnikoff. Nature Immunology, 9, 705-712.
[30] Björkman, I., Röing, M., Sternberg Lewerin, S., Stålsby Lundborg, C. and Eriksen, J. (2021) Animal Production with Restrictive Use of Antibiotics to Contain Antimicrobial Resistance in Sweden—A Qualitative Study. Frontiers in Veterinary Science, 7, Article ID: 619030.
[31] Mullenix, G.J., Greene, E.S., Emami, N.K., Tellez-Isaias, G., Bottje, W.G., Erf, G.F., et al. (2021) Spirulina platensis Inclusion Reverses Circulating Pro-Inflammatory (Chemo) Cytokine Profiles in Broilers Fed Low-Protein Diets. Frontiers in Veterinary Science, 8, Article ID: 640968.
[32] Sylte, M.J., Sivasankaran, S.K., Trachsel, J., Sato, Y., Wu, Z., Johnson, T.A., et al. (2021) The Acute Host-Response of Turkeys Colonized with Campylobacter coli. Frontiers in Veterinary Science, 8, Article ID: 613203.
[33] Takano, T., Satoh, K. and Doki, T. (2021) Possible Antiviral Activity of 5-Aminolevulinic Acid in Feline Infectious Peritonitis Virus (Feline Coronavirus) Infection. Frontiers in Veterinary Science, 8, Article ID: 647189.
[34] Fasano, A. (2020) All Disease Begins in the (Leaky) Gut: Role of Zonulin-Mediated Gut Permeability in the Pathogenesis of Some Chronic Inflammatory Diseases. F1000Research, 9, F1000.
[35] Sekirov, I., Russell, S.L., Antunes, L.C.M. and Finlay, B.B. (2010) Gut Microbiota in Health and Disease. Physiological Reviews, 90, 859-904.
[36] Dimitrov, D.V. (2011) The Human Gutome: Nutrigenomics of the Host-Microbiome Interactions. OMICS, 15, 419-430.
[37] Wu, R.Y., Määttänen, P., Napper, S., Scruten, E., Li, B., Koike, Y., et al. (2017) Non-Digestible Oligosaccharides Directly Regulate Host Kinome to Modulate Host Inflammatory Responses Without Alterations in the Gut Microbiota. Microbiome, 5, 135.
[38] Fukui, H., Xu, X. and Miwa, H. (2018) Role of Gut Microbiota-Gut Hormone Axis in the Pathophysiology of Functional Gastrointestinal Disorders. Journal of Neurogastroenterology and Motility, 24, 367.
[39] Megur, A., Baltriukienè, D., Bukelskienè, V. and Burokas, A. (2021) The Microbiota-Gut-Brain Axis and Alzheimer’s Disease: Neuroinflammation Is to Blame? Nutrients, 13, 37.
[40] Neuman, H., Debelius, J.W., Knight, R. and Koren, O. (2015) Microbial Endocrinology: The Interplay between the Microbiota and the Endocrine System. FEMS Microbiology Reviews, 39, 509-521.
[41] Maslowski, K.M. and Mackay, C.R. (2010) Diet, Gut Microbiota and Immune Responses. Nature Immunology, 12, 5-9.
[42] Tellez, G., Higgins, S., Donoghue, A. and Hargis, B. (2006) Digestive Physiology and the Role of Microorganisms. Journal of Applied Poultry Research, 15, 136-144.
[43] Liu, X., Cao, S. and Zhang, X. (2015) Modulation of Gut Microbiota-Brain Axis by Probiotics, Prebiotics, and Diet. Journal of Agricultural and Food Chemistry, 63, 7885-7895.
[44] Chalvon-Demersay, T., Luise, D., Floc’h, L., Tesseraud, S., Lambert, W., Bosi, P., et al. (2021) Functional Amino Acids in Pigs and Chickens: Implication for Gut Health. Frontiers in Veterinary Science, 8, Article ID: 663727.
[45] Tlaskalová-Hogenová, H., Stepánková, R., Hudcovic, T., Tucková, L., Cukrowska, B., Lodinová-Zádniková, R., et al. (2004) Commensal Bacteria (Normal Microflora), Mucosal Immunity and Chronic Inflammatory and Autoimmune Diseases. Immunology Letters, 93, 97-108.
[46] Weiss, G.A. and Hennet, T. (2017) Mechanisms and Consequences of Intestinal Dysbiosis. Cellular and Molecular Life Sciences, 74, 2959-2977.
[47] Tellez, G., Latorre, J.D., Kuttappan, V.A., Kogut, M.H., Wolfenden, A., Hernandez-Velasco, X., et al. (2014) Utilization of Rye as Energy Source Affects Bacterial Translocation, Intestinal Viscosity, Microbiota Composition, and Bone Mineralization in Broiler Chickens. Frontiers in Veterinary Science, 5, 339.
[48] Zareie, M., Johnson-Henry, K., Jury, J., Yang, P.-C., Ngan, B.-Y., McKay, D.M., et al. (2006) Probiotics Prevent Bacterial Translocation and Improve Intestinal Barrier Function in Rats Following Chronic Psychological Stress. Gut, 55, 1553-1560.
[49] Kallapura, G., Pumford, N.R., Hernandez-Velasco, X., Hargis, B.M. and Tellez, G. (2014) Mechanisms Involved in Lipopolysaccharide Derived ROS and RNS Oxidative Stress and Septic Shock. Journal of Microbiology Research and Reviews, 2, 6-11.
[50] Stecher, B. (2015) The Roles of Inflammation, Nutrient Availability and the Commensal Microbiota in Enteric Pathogen Infection. Microbiology Spectrum, 3, 3.
[51] Iebba, V., Totino, V., Gagliardi, A., Santangelo, F., Cacciotti, F., Trancassini, M., et al. (2016) Eubiosis and Dysbiosis: The Two Sides of the Microbiota. The New Microbiologica, 39, 1-12.
[52] Lopetuso, L.R., Scaldaferri, F., Petito, V. and Gasbarrini, A. (2013) Commensal Clostridia: Leading Players in the Maintenance of Gut Homeostasis. Gut Pathogens, 5, 23.
[53] Zhong, Y., Teixeira, C., Marungruang, N., Sae-Lim, W., Tareke, E. andersson, R., et al. (2015) Barley Malt Increases Hindgut and Portal Butyric Acid, Modulates Gene Expression of Gut Tight Junction Proteins and Toll-Like Receptors in Rats Fed High-Fat Diets, But High Advanced Glycation End-Products Partially Attenuate the Effects. Food and Function, 6, 3165-3176.
[54] Honneffer, J.B., Minamoto, Y. and Suchodolski, J.S. (2014) Microbiota Alterations in Acute and Chronic Gastrointestinal Inflammation of Cats and Dogs. World Journal of Gastroenterology, 20, Article ID: 16489.
[55] Flint, H.J., Bayer, E.A., Rincon, M.T., Lamed, R. and White, B.A. (2008) Polysaccharide Utilization by Gut Bacteria: Potential for New Insights from Genomic Analysis. Nature Reviews Microbiology, 6, 121-131.
[56] Kabeerdoss, J., Sankaran, V., Pugazhendhi, S. and Ramakrishna, B.S. (2013) Clostridium leptum Group Bacteria Abundance and Diversity in the Fecal Microbiota of Patients with Inflammatory Bowel Disease: A Case-Control Study in India. BMC Gastroenterology, 13, 20.
[57] Wahl, S.M., Swisher, J., McCartney-Francis, N. and Chen, W. (2004) TGF-beta: The Perpetrator of Immune Suppression by Regulatory T Cells and Suicidal T Cells. Journal of Leukocyte Biology, 76, 15-24.
[58] Bergman, E.N. (1990) Energy Contributions of Volatile Fatty Acids from the Gastrointestinal Tract in Various Species. Physiologycal Reviews, 70, 567-590.
[59] Schnabl, B. and Brenner, D.A. (2014) Interactions between the Intestinal Microbiome and Liver Diseases. Gastroenterology, 146, 1513-1524.
[60] Segain, J., De La Blétiere, D.R., Bourreille, A., Leray, V., Gervois, N., Rosales, C., et al. (2000) Butyrate Inhibits Inflammatory Responses through NFκB Inhibition: Implications for Crohn’s Disease. Gut, 47, 397-403.
[61] Livanos, A.E., Snider, E.J., Whittier, S., Chong, D.H., Wang, T.C., Abrams, J.A., et al. (2018) Rapid Gastrointestinal Loss of Clostridial Clusters IV and XIVa in the ICU Associates with an Expansion of Gut Pathogens. PLOS ONE, 13, e0200322.
[62] Takahashi, M., Taguchi, H., Yamaguchi, H., Osaki, T., Komatsu, A. and Kamiya, S. (2004) The Effect of Probiotic Treatment with Clostridium butyricum on Enterohemorrhagic Escherichia coli O157: H7 Infection in Mice. FEMS Immunology and Medical Microbiology, 41, 219-226.
[63] Fukuda, S., Toh, H., Hase, K., Oshima, K., Nakanishi, Y., Yoshimura, K., et al. (2011) Bifidobacteria Can Protect from Enteropathogenic Infection through Production of Acetate. Nature, 469, 543-547.
[64] Oakley, B.B., Buhr, R.J., Ritz, C.W., Kiepper, B.H., Berrang, M.E., Seal, B.S., et al. (2014) Successional Changes in the Chicken Cecal Microbiome during 42 Days of Growth Are Independent of Organic Acid Feed Additives. BMC Veterinary Research, 10, 282.
[65] Rajput, D.S., Zeng, D., Khalique, A., Rajput, S.S., Wang, H., Zhao, Y., et al. (2020) Pretreatment with Probiotics Ameliorate Gut Health and Necrotic Enteritis in Broiler Chickens, a Substitute to Antibiotics. AMB Express, 10, 220.
[66] Kan, L., Guo, F., Liu, Y., Pham, V.H., Guo, Y. and Wang, Z. (2021) Probiotics Bacillus licheniformis Improves Intestinal Health of Subclinical Necrotic Enteritis-Challenged Broilers. Frontiers in Microbiology, 12, Article ID: 623739.
[67] Khalique, A., Zeng, D., Shoaib, M., Wang, H., Qing, X., Rajput, D.S., et al. (2020) Probiotics Mitigating Subclinical Necrotic Enteritis (SNE) as Potential Alternatives to Antibiotics in Poultry. AMB Express, 10, 50.
[68] Shojadoost, B., Vince, A.R. and Prescott, J.F. (2012) The Successful Experimental induction of Necrotic Enteritis in Chickens by Clostridium perfringens: A Critical Review. Veterinary Research, 43, 1-12.
[69] Branton, S.L., Lott, B.D., Deaton, J.W., Maslin, W.R., Austin, F.W., Pote, L.M., et al. (1997) The Effect of Added Complex Carbohydrates or Added Dietary Fiber on Necrotic Enteritis Lesions in Broiler Chickens. Poultry Science, 76, 24-28.
[70] Shivaramaiah, S., Wolfenden, R.E., Barta, J.R., Morgan, M.J., Wolfenden, A.D., Hargis, B.M., et al. (2011) The Role of an Early Salmonella typhimurium Infection as a Predisposing Factor for Necrotic Enteritis in a Laboratory Challenge Model. Avian Diseases, 55, 319-323.
[71] Willemsen, L.E.M., Koetsier, M.A., Van Deventer, S.J.H. and Van Tol, E.A.F. (2003) Short Chain Fatty Acids Stimulate Epithelial Mucin 2 Expression through Differential Effects on Prostaglandin E1 and E2 Production by Intestinal Myofibroblasts. Gut, 52, 1442-1447.
[72] Cox, C.M., Sumners, L.H., Kim, S., McElroy, A.P., Bedford, M.R. and Dalloul, R.A. (2010) Immune Responses to Dietary β-Glucan in Broiler Chicks during an Eimeria Challenge. Poultry Science, 89, 2597-2607.
[73] Abd El-Hack, M.E., El-Saadony, M.T., Elbestawy, A.R., Nahed, A., Saad, A.M., Salem, H.M., et al. (2021) Necrotic Enteritis in Broiler Chickens: Disease Characteristics and Prevention Using Organic Antibiotic Alternatives: A Comprehensive Review. Poultry Science, 101, Article ID: 101590.
[74] Van der Sluis, W. (2000) Clostridial Enteritis Is an Often Underestimated Problem. World’s Poultry Science Journal, 16, 42-43.
[75] Statista (2021) Number of Chickens Worldwide from 1990 to 2020.
[76] Broom, L. (2017) Necrotic Enteritis; Current Knowledge and Diet-Related Mitigation. World’s Poultry Science Journal, 73, 281-292.
[77] Emami, N.K. and Dalloul, R.A. (2021) Centennial Review: Recent Developments in Host-Pathogen Interactions during Necrotic Enteritis in Poultry. Poultry Science, 100, Article ID: 101330.
[78] McDonel, J.L. (1980) Clostridium perfringens Toxins (Type A, B, C, D, E). Pharmacology and Therapeutics, 10, 617-655.
[79] Uzal, F.A., Freedman, J.C., Shrestha, A., Theoret, J.R., Garcia, J., Awad, M.M., et al. (2014) Towards an Understanding of the Role of Clostridium perfringens Toxins in Human and Animal Disease. Future Microbiology, 9, 361-377.
[80] Nagahama, M., Ochi, S., Oda, M., Miyamoto, K., Takehara, M. and Kobayashi, K. (2015) Recent Insights into Clostridium perfringens Beta-Toxin. Toxins, 7, 396-406.
[81] Labbe, R. and Huang, T. (1995) Generation Times and Modeling of Enterotoxin-Positive and Enterotoxin-Negative Strains of Clostridium perfringens in Laboratory Media and Ground Beef. Journal of Food Protection, 58, 1303-1306.
[82] Kulkarni, R., Parreira, V., Sharif, S. and Prescott, J. (2007) Immunization of Broiler Chickens against Clostridium perfringens-Induced Necrotic Enteritis. Clinical and Vaccine Immunology, 14, 1070-1077.
[83] Timbermont, L., Haesebrouck, F., Ducatelle, R. and Van Immerseel, F. (2011) Necrotic Enteritis in Broilers: An Updated Review on the Pathogenesis. Avian Pathology, 40, 341-347.
[84] Timbermont, L., Lanckriet, A., Dewulf, J., Nollet, N., Schwarzer, K., Haesebrouck, F., et al. (2010) Control of Clostridium perfringens-Induced Necrotic Enteritis in Broilers by Target-Released Butyric Acid, Fatty Acids and Essential Oils. Avian Pathology, 39, 117-121.
[85] McReynolds, J., Byrd, J. anderson, R., Moore, R., Edrington, T., Genovese, K., et al. (2004) Evaluation of Immunosuppressants and Dietary Mechanisms in an Experimental Disease Model for Necrotic Enteritis. Poultry Science, 83, 1948-1952.
[86] Caly, D.L., D’Inca, R., Auclair, E. and Drider, D. (2015) Alternatives to Antibiotics to Prevent Necrotic Enteritis in Broiler Chickens: A Microbiologist’s Perspective. Frontiers in Microbiology, 6, 1336.
[87] Riaz, A., Umar, S., Munir, M.T. and Tariq, M. (2017) Replacements of Antibiotics in the Control of Necrotic Enteritis: A Review. Science Letters, 5, 208-216.
[88] Emami, N.K., White, M.B., Calik, A., Kimminau, E.A. and Dalloul, R.A. (2021) Managing Broilers Gut Health with Antibiotic-Free Diets during Subclinical Necrotic Enteritis. Poultry Science, 100, Article ID: 101055.
[89] Moore, R.J. (2016) Necrotic Enteritis Predisposing Factors in Broiler Chickens. Avian Pathology, 45, 275-281.
[90] Riddell, C. and Kong, X.M. (1992) The Influence of Diet on Necrotic Enteritis in Broiler Chickens. Avian Diseases, 36, 499-503.
[91] Branton, S.L., Reece, F.N. and Hagler Jr., WM. (1987) Influence of a Wheat Diet on Mortality of Broiler Chickens Associated with Necrotic Enteritis. Poultry Science, 66, 1326-1330.
[92] Allaart, J.G., van Asten, A.J.A.M. and Gröne, A. (2013) Predisposing Factors and Prevention of Clostridium perfringens-Associated Enteritis. Comparative Immunology Microbiology and Infectious Diseases, 36, 449-464.
[93] Cogliani, C., Goossens, H. and Greko, C. (2011) Restricting Antimicrobial Use in Food Animals: Lessons from Europe: Banning Nonessential Antibiotic Uses in Food Animals Is Intended to Reduce Pools of Resistance Genes. Microbe Magazine, 6, 274-279.
[94] Tellez, G., Laukova, A., Latorre, A., Hernandez-Velasco, X., Hargis, B. and Callaway, T. (2015) Food-Producing Animals and Their Health in Relation to Human Health. Microbial Ecology in Health and Disease, 26, 25876.
[95] Tellez-Isaias, V., Christine, N., Brittany, D., Callie, M., Lucas, E., Roberto, S, et al. (2021) Developing Probiotics, Prebiotics, and Organic Acids to Control Salmonella spp. in Commercial Turkeys at the University of Arkansas USA. German Journal of Veterinary Research, 1, 7-12.
[96] Wu, Y., Zhen, W., Geng, Y., Wang, Z. and Guo, Y. (2019) Pretreatment with Probiotic Enterococcus faecium NCIMB 11181 Ameliorates Necrotic Enteritis-Induced Intestinal Barrier Injury in Broiler Chickens. Scientific Reports, 9, Article No. 10256.
[97] Latorre, J.D., Hernandez-Velasco, X., Wolfenden, R.E., Vicente, J.L., Wolfenden, A.D., Menconi, A., et al. (2016) Evaluation and Selection of Bacillus Species Based on Enzyme Production, Antimicrobial Activity, and Biofilm Synthesis as Direct-Fed Microbial Candidates for Poultry. Frontiers in Veterinary Science, 3, 95.
[98] Knap, I., Lund, B., Kehlet, A.B., Hofacre, C. and Mathis, G. (2010) Bacillus licheniformis Prevents Necrotic Enteritis in Broiler Chickens. Avian Diseases, 54, 931-935.
[99] Aljumaah, M.R., Alkhulaifi, M.M., Abudabos, A.M., Aljumaah, R.S., Alsaleh, A.N. and Stanley, D. (2020) Bacillus subtilis PB6 Based Probiotic Supplementation Plays a Role in the Recovery after the Necrotic Enteritis Challenge. PLOS ONE, 15, e0232781.
[100] Torres-Rodriguez, A., Higgins, S., Vicente, J., Wolfenden, A., Gaona-Ramirez, G., Barton, J., et al. (2007) Effect of Lactose as a Prebiotic on Turkey Body Weight under Commercial Conditions. Journal of Applied Poultry Research, 16, 635-641.
[101] Hernandez-Patlan, D., Solis-Cruz, B., Patrin Pontin, K., Latorre, J.D., Baxter, M.F., Hernandez-Velasco, X., et al. (2019) Evaluation of the Dietary Supplementation of a Formulation Containing Ascorbic Acid and a Solid Dispersion of Curcumin with Boric Acid against Salmonella Enteritidis and Necrotic Enteritis in Broiler Chickens. Animals, 9, 184.
[102] Leyva-Diaz, A.A., Hernandez-Patlan, D., Solis-Cruz, B., Adhikari, B., Kwon, Y.M., Latorre, J.D., et al. (2021) Evaluation of Curcumin and Copper Acetate against Salmonella typhimurium Infection, Intestinal Permeability, and Cecal Microbiota Composition in Broiler Chickens. Journal of Animal Science and Biotechnology, 12, 23.
[103] Ruff, J., Barros, T.L., Tellez Jr., G., Blankenship, J., Lester, H., Graham, B.D., et al. (2020) Research Note: Evaluation of a Heat Stress Model to Induce Gastrointestinal Leakage in Broiler Chickens. Poultry Science, 99, 1687-1692.
[104] Baxter, M.F., Greene, E.S., Kidd, M.T., Tellez-Isaias, G., Orlowski, S. and Dridi, S. (2020) Water Amino Acid-Chelated Trace Mineral Supplementation Decreases Circulating and Intestinal HSP70 and Proinflammatory Cytokine Gene Expression in Heat-Stressed Broiler Chickens. Journal of Animal Science, 98, skaa049.
[105] Hernandez-Patlan, D., Solis-Cruz, B., Pontin, K.P., Latorre, J.D., Baxter, M.F., Hernandez-Velasco, X., et al. (2018) Evaluation of a Solid Dispersion of Curcumin with Polyvinylpyrrolidone and Boric Acid against Salmonella enteritidis Infection and intestinal Permeability in Broiler Chickens: A Pilot Study. Frontiers in Microbiology, 9, 1289.
[106] Solis-Cruz, B., Hernandez-Patlan, D., Petrone, V.M., Pontin, K.P., Latorre, J.D., Beyssac, E., et al. (2019) Evaluation of a Bacillus-Based Direct-Fed Microbial on Aflatoxin B1 Toxic Effects, Performance, Immunologic Status, and Serum Biochemical Parameters in Broiler Chickens. Avian Diseases, 63, 659-669.
[107] Petrone-Garcia, V.M., Lopez-Arellano, R., Patiño, G.R., Rodríguez, M.A.C., Hernandez-Patlan, D., Solis-Cruz, B., et al. (2021) Curcumin Reduces Enteric Isoprostane 8-Iso-PGF2α and Prostaglandin GF2α in Specific Pathogen-Free Leghorn Chickens Challenged with Eimeria maxima. Scientific Reports, 11, Article No. 11609.
[108] Bakkali, F., Averbeck, S., Averbeck, D. and Idaomar, M. (2008) Biological Effects of Essential Oils—A Review. Food Chemical Toxicology, 46, 446-475.
[109] Burt, S. (2004) Essential Oils: Their Antibacterial Properties and Potential Applications in Foods—A Review. International Journal of Food Microbiology, 94, 223-253.
[110] Arfa, A.B., Combes, S., Preziosi-Belloy, L., Gontard, N. and Chalier, P. (2006) Antimicrobial Activity of Carvacrol Related to Its Chemical Structure. Letters in Applied Microbiology, 43, 149-154.
[111] Mzabi, A., Tanghort, M., Chefchaou, H., Moussa, H., Chami, N., Chami, F., et al. (2019) A Comparative Study of the Anticlostridial Activity of Selected Essential Oils, Their Major Components and a Natural Product with Antibiotics. International Journal Poultry Science, 18, 187-194.
[112] Franz, C., Baser, K. and Windisch, W. (2010) Essential Oils and Aromatic Plants in Animal Feeding—A European Perspective. A Review. Flavour and Fragrance Journal, 25, 327-340.
[113] Gopi, M., Karthik, K., Manjunathachar, H.V., Tamilmahan, P., Kesavan, M., Dashprakash, M., et al. (2014) Essential Oils as a Feed Additive in Poultry Nutrition. Advances in Animal and Veterinary Sciences, 2, 1-7.
[114] He, X., Hao, D., Liu, C., Zhang, X., Xu, D., Xu, X., Wang, J. and Wu, R. (2017) Effect of Supplemental Oregano Essential Oils in Diets on Production Performance and Relatively Intestinal Parameters of Laying Hens. American Journal of Molecular Biology, 7, 73-85.
[115] Snow Setzer, M., Sharifi-Rad, J. and Setzer, W.N. (2016) The Search for Herbal Antibiotics: An In-Silico Investigation of Antibacterial Phytochemicals. Antibiotics, 5, 30.
[116] Yanishlieva, N.V., Marinova, E.M., Gordon, M.H. and Raneva, V.G. (1999) Antioxidant Activity and Mechanism of Action of Thymol and Carvacrol in Two Lipid Systems. Food Chemistry, 64, 59-66.
[117] Eid, N., Dahshan, A., El-Nahass, E.-S., Shalaby, B. and Ali, A. (2018) Anticlostridial Activity of the Thyme and Clove Essential Oils against Experimentally Induced Necrotic Enteritis in Commercial Broiler Chickens. Veterinary Science Research and Reviews, 4, 25-34.
[118] Gharaibeh, M.H., Khalifeh, M.S., Nawasreh, A.N., Hananeh, W.M. and Awawdeh, M.S. (2012) Assessment of Immune Response and Efficacy of Essential Oils Application on Controlling Necrotic Enteritis Induced by Clostridium perfringens in Broiler Chickens. Molecules, 26, 4527.
[119] Yang, C., Kennes, Y.M., Lepp, D., Yin, X., Wang, Q., Yu, H., et al. (2020) Effects of Encapsulated Cinnamaldehyde and Citral on the Performance and Cecal Microbiota of Broilers Vaccinated or Not Vaccinated against Coccidiosis. Poultry Science, 99, 936-948.
[120] McReynolds, J., Waneck, C., Byrd, J., Genovese, K., Duke, S. and Nisbet, D. (2009) Efficacy of Multistrain Direct-Fed Microbial and Phytogenetic Products in Reducing Necrotic Enteritis in Commercial Broilers. Poultry Science, 88, 2075-2080.
[121] Lu, P.D. and Zhao, Y.H. (2020) Targeting NF-κB Pathway for Treating Ulcerative Colitis: Comprehensive Regulatory Characteristics of Chinese Medicines. Chinese Medicine, 15, 15.
[122] Du, E. and Guo, Y. (2021) Dietary Supplementation of Essential Oils and Lysozyme Reduces Mortality and Improves Intestinal Integrity of Broiler Chickens with Necrotic Enteritis. Animal Science Journal, 92, e13499.
[123] Pham, V.H., Kan, L., Huang, J., Geng, Y., Zhen, W., Guo, Y., et al. (2020) Dietary Encapsulated Essential Oils and Organic Acids Mixture Improves Gut Health in Broiler Chickens Challenged with Necrotic Enteritis. Journal of Animal Science and Biotechnology, 11, 18.
[124] Si, W., Ni, X., Gong, J., Yu, H., Tsao, R., Han, Y., et al. (2009) Antimicrobial Activity of Essential Oils and Structurally Related Synthetic Food Additives towards Clostridium perfringens. Journal of Applied Microbiology, 106, 213-220.
[125] Engberg, R.M., Grevsen, K., Ivarsen, E., Fretté, X., Christensen, L.P., Højberg, O., et al. (2012) The Effect of Artemisia annua on Broiler Performance, on Intestinal Microbiota and on the Course of a Clostridium perfringens Infection Applying a Necrotic Enteritis Disease Model. Avian Pathology, 41, 369-376.
[126] Yin, D., Du, E., Yuan, J., Gao, J., Wang, Y., Aggrey, S.E., et al. (2017) Supplemental Thymol and Carvacrol Increases Ileum Lactobacillus Population and Reduces Effect of Necrotic Enteritis Caused by Clostridium perfringes in Chickens. Scientific Report, 7, Article No. 7334.
[127] Kumar, A., Toghyani, M., Kheravii, S.K., Pineda, L., Han, Y., Swick, R.A., et al. (2022) Organic Acid Blends Improve Intestinal Integrity, Modulate Short-Chain Fatty Acids Profiles and Alter Microbiota of Broilers under Necrotic Enteritis Challenge. Animal Nutrition, 8, 82-90.
[128] Pham, V.H., Abbas, W., Huang, J., He, Q., Zhen, W., Guo, Y., et al. (2022) Effect of Blending Encapsulated Essential Oils and Organic Acids as an Antibiotic Growth Promoter Alternative on Growth Performance and Intestinal Health in Broilers with Necrotic Enteritis. Poultry Science, 101, Article ID: 101563.
[129] Kumar, A., Sharma, N.K., Kheravii, S.K., Keerqin, C., Ionescu, C., Blanchard, A., et al. (2022) Potential of a Mixture of Eugenol and Garlic Tincture to Improve Performance and Intestinal Health in Broilers under Necrotic Enteritis Challenge. Animal Nutrition, 8, 26-37.
[130] Bortoluzzi, C., Rothrock, M.J., Vieira, B.S., Mallo, J.J., Puyalto, M., Hofacre, C., et al. (2018) Supplementation of Protected Sodium Butyrate Alone or in Combination with Essential Oils Modulated the Cecal Microbiota of Broiler Chickens Challenged with Coccidia and Clostridium perfringens. Frontiers in Sustainable Food Systems, 2, 72.
[131] Abdelli, N., Pérez, J.F., Vilarrasa, E., Melo-Duran, D., Cabeza Luna, I., Karimirad, R., et al. (2021) Microencapsulation Improved Fumaric Acid and Thymol Effects on Broiler Chickens Challenged with a Short-Term Fasting Period. Frontiers in Veterinary Science, 8, Article ID: 686143.
[132] Abdelli, N., Pérez, J.F., Vilarrasa, E., Cabeza Luna, I., Melo-Duran, D., D’Angelo, M., et al. (2020) Targeted-Release Organic Acids and Essential Oils Improve Performance and Digestive Function in Broilers under a Necrotic Enteritis Challenge. Animals, 10, 259.
[133] Kim, D.K., Lillehoj, H.S., Lee, S.H., Jang, S.I. and Bravo, D. (2010) High-Throughput Gene Expression Analysis of Intestinal Intraepithelial Lymphocytes after Oral Feeding of Carvacrol, Cinnamaldehyde, or Capsicum Oleoresin. Poultry Science, 89, 68-81.
[134] Du, E., Wang, W., Gan, L., Li, Z., Guo, S. and Guo, Y. (2016) Effects of Thymol and Carvacrol Supplementation on Intestinal Integrity and Immune Response of Broiler Chickens Challenged with Clostridium perfringens. Journal of Animal Science and Biotechnology, 7, 1-10.
[135] Jerzsele, A., Szeker, K., Csizinszky, R., Gere, E., Jakab, C., Mallo, I.I., et al. (2012) Ef-ficacy of Protected Sodium Butyrate, a Protected Blend of Essential Oils, Their Combination, and Bacillus amyloliquefaciens Spore Suspension against Artificially Induced Necrotic Enteritis in Broilers. Poultry Science, 91, 837-843.
[136] Lee, S.H., Lillehoj, H.S., Jang, S.I., Lillehoj, E.P., Min, W. and Bravo, D.M. (2013) Dietary Supplementation of Young Broiler Chickens with Capsicum and Turmeric Oleoresins Increase Resistance to Necrotic Enteritis. British Journal of Nutrition, 110, 840-847.
[137] Liu, Y., Yang, X., Xin, H., Chen, S., Yang, C. and Duan, Y. (2017) Effects of a Protected Inclusion of Organic Acids and Essential Oils as Antibiotic Growth Promoter Alternative on Growth Performance, Intestinal Morphology and Gut Microflora in Broilers. Animal Science Journal, 88, 1414-1424.
[138] Sorour, H.K., Hosny, R.A. and Elmasry, D.M.A. (2021) Effect of Peppermint Oil and Its Microemulsion on Necrotic Enteritis in Broiler Chickens. Veterinary World, 14, 483-491.
[139] Ibrahim, D., Ismail, T.A., Khalifa, E., El-Kader, S.A.A., Mohamed, D.I., Mohamed, D.T., et al. (2021) Supplementing Garlic Nanohydrogel Optimized Growth, Gastrointestinal Integrity and Economics and Ameliorated Necrotic Enteritis in Broiler Chickens Using a Clostridium perfringens Challenge Model. Animals, 11, 2027.
[140] Moharreri, M., Vakili, R., Oskoueian, E. and Rajabzadeh, G. (2021) Phytobiotic Role of Essential Oil-Loaded Microcapsules in Improving the Health Parameters in Clostridium perfringens-Infected Broiler Chickens. Italian Journal of Animal Science, 20, 2075-2085.
[141] Jin, X., Huang, G., Luo, Z., Hu, Y. and Liu, D. (2022) Oregano (Origanum vulgare L.) Essential Oil Feed Supplement Protected Broilers Chickens against Clostridium perfringens Induced Necrotic Enteritis. Agriculture, 12, 18.
[142] Yan, X., Liu, Y., Yan, F., Yang, C. and Yang, X. (2019) Effects of Encapsulated Organic Acids and Essential Oils on Intestinal Barrier, Microbial Count, and Bacterial Metabolites in Broiler Chickens. Poultry Science, 98, 2858-2865.
[143] Stefanello, C., Rosa, D.P., Dalmoro, Y.K., Segatto, A.L., Vieira, M.S., Moraes, M.L., et al. (2020) Protected Blend of Organic Acids and Essential Oils Improves Growth Performance, Nutrient Digestibility, and Intestinal Health of Broiler Chickens Undergoing an Intestinal Challenge. Frontiers in Veterinary Science, 6, 491.
[144] Tiihonen, K., Kettunen, H., Bento, M.H.L., Saarinen, M., Lahtinen, S., Ouwehand, A.C., et al. (2010) The Effect of Feeding Essential Oils on Broiler Performance and Gut Microbiota. British Poultry Science, 51, 381-392.
[145] Brenes, A. and Roura, E. (2010) Essential Oils in Poultry Nutrition: Main Effects and Modes of Action. Animal Feed Science and Technology, 158, 1-14.
[146] Kuttappan, V., Berghman, L., Vicuña, E., Latorre, J., Menconi, A., Wolchok, J., et al. (2015) Poultry Enteric Inflammation Model with Dextran Sodium Sulfate Mediated Chemical Induction and Feed Restriction in Broilers. Poultry Science, 94, 1220-1226.
[147] Vicuña, E., Kuttappan, V., Galarza-Seeber, R., Latorre, J., Faulkner, O., Hargis, B., et al. (2015) Effect of Dexamethasone in Feed on Intestinal Permeability, Differential White Blood Cell Counts, and Immune Organs in Broiler Chicks. Poultry Science, 94, 2075-2080.
[148] Menconi, A., Hernandez-Velasco, X., Vicuña, E., Kuttappan, V., Faulkner, O., Tellez, G., et al. (2015) Histopathological and Morphometric Changes Induced by a Dextran Sodium Sulfate (DSS) Model in Broilers. Poultry Science, 94, 906-911.
[149] Latorre, J.D., Adhikari, B., Park, S.H., Teague, K.D., Graham, L.E., Mahaffey, B.D., et al. (2018) Evaluation of the Epithelial Barrier Function and Ileal Microbiome in an Established Necrotic Enteritis Challenge Model in Broiler Chickens. Frontiers in Veterinary Science, 5, 199.
[150] Baxter, M.F., Merino-Guzman, R., Latorre, J.D., Mahaffey, B.D., Yang, Y., Teague, K.D., et al. (2017) Optimizing Fluorescein Isothiocyanate Dextran Measurement as a Biomarker in a 24-h Feed Restriction Model to Induce Gut Permeability in Broiler Chickens. Frontiers in Veterinary Science, 4, 56.
[151] Vuong, C.N., Mullenix, G.J., Kidd, M.T., Bottje, W.G., Hargis, B.M. and Tellez-Isaias G. (2021) Research Note: Modified Serum Fluorescein Isothiocyanate Dextran (FITC-D) Assay Procedure to Determine Intestinal Permeability in Poultry Fed Diets High in Natural or Synthetic Pigments. Poultry Science, 100, Article ID: 101138.
[152] Baxter, M.F., Latorre, J.D., Dridi, S., Merino-Guzman, R., Hernandez-Velasco, X., Hargis, B.M., et al. (2019) Identification of Serum Biomarkers for Intestinal Integrity in a Broiler Chicken Malabsorption Model. Frontiers in Veterinary Science, 6, 144.
[153] Tellez Jr, G., Arreguin-Nava, M., Maguey, J., Michel, M., Latorre, J., Merino-Guzman, R., et al. (2020) Effect of Bacillus-Direct-Fed Microbial on Leaky Gut, Serum Peptide YY Concentration, Bone Mineralization, and Ammonia Excretion in Neonatal Female Turkey Poults Fed with a Rye-Based Diet. Poultry Science, 99, 4514-4520.
[154] Kerr, M.A. (2000) Function of Immunoglobulin A in Immunity. Gut, 47, 751-752.
[155] Hermans, D., Pasmans, F., Heyndrickx, M., Van Immerseel, F., Martel, A., Van Deun, K., et al. (2012) A Tolerogenic Mucosal Immune Response Leads to Persistent Campylobacter jejuni Colonization in the Chicken Gut. Critical Reviews in Microbiology, 38, 17-29.
[156] Lin, F.C. and Young, H.A. (2013) The Talented Interferon-Gamma. Advances in Bioscience and Biotechnology, 4, 6-13.
[157] Betteridge, D.J. (2000) What Is Oxidative Stress? Metabolism, 49, 3-8.
[158] Surai, P.F. (2016) Antioxidant Systems in Poultry Biology: Superoxide Dismutase. Journal of Animal Research and Nutrition, 1, 8.
[159] Chen, J., Tellez, G., Richards, J.D. and Escobar, J. (2015) Identification of Potential Biomarkers for Gut Barrier Failure in Broiler Chickens. Frontiers in Veterinary Science, 2, 14.
[160] Matter, K. and Balda, M.S. (2007) Epithelial Tight Junctions, Gene Expression and Nucleojunctional Interplay. Journal of Cell Science, 120, 1505-1511.
[161] Tsiouris, V. (2016) Poultry Management: A Useful Tool for the Control of Necrotic Enteritis in Poultry. Avian Pathology, 45, 323-325.
[162] Mot, D., Timbermont, L., Haesebrouck, F., Ducatelle, R. and Van Immerseel, F. (2014) Progress and Problems in Vaccination against Necrotic Enteritis in Broiler Chickens. Avian Pathology, 43, 290-300.
[163] Van Waeyenberghe, L., De Gussem, M., Verbeke, J., Dewaele, I. and De Gussem, J. (2016) Timing of Predisposing Factors Is Important in Necrotic Enteritis Models. Avian Pathology, 45, 370-375.

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